Following the proverb “They meet by clothes …”, let’s start the review with designer models of radiators and heated towel rails for bathrooms. This segment traditionally presents a large number of Arbonia, Kermi, Cordivari, Zehnder products of a wide variety of shapes and colors, moreover, made of various materials. Models with a staircase-shaped body are popular — a pair of vertical profiles on the sides, and between them a number of horizontal pipes, as, for example, in the models of the Basic-50 (Kermi) or Toga (Zehnder) series. On such a radiator, you can hang wet towels or clothes. A similar design option — bearing vertical profiles are located in the center, and horizontal pipes extend sideways from them, like branches from a tree trunk (Yucca (Zehnder), Babula (Cordivari), Zeta (Kimrsky heating equipment plant) lines. Pipes can be round in cross section or flat, as in the Giuly (Cordivari) series, located strictly symmetrically with respect to vertical profiles or placed in one direction — there are many varieties of design radiators.
Much more interesting, however, are technical innovations in “ordinary”, non-designer devices. The largest number of innovations in this segment relates to the improvement of the geometry of the hull so that it is better flowed around by air currents. So, in the Revolution (Royal Thermo) models, the ribs have a wavy shape, so that the air does not stagnate, its circulation improves, and heat transfer increases by 5%. The Indigo (Royal Thermo) models feature reverse convection. The design of the upper part of the radiator forms a reverse flow of hot air, effectively cutting off the cold from the windows. Improved and internal details. For example, Kermi steel radiators use therm-x2 technology, which allows the coolant to flow sequentially through the radiator panels. Thanks to this technology, efficiency is achieved, which until now was considered unattainable in the segment of steel panel radiators. New types of radiators are also appearing, such as Kermi panel models with an installation height of 200 mm, which are suitable for panoramic structures, as well as verandas, conservatories and other rooms with large windows or low window sills.
Decorative radiators are distinguished by a variety of shapes and are quite capable of becoming a key element of the interior of the room.
Another improvement was proposed by Rifar manufacturers. Their sectional radiators BASE 200/350/500, ALUM 350/500, FORZA 350/500, ALP 500 can be completed with a towel holder. It turns out a comfortable and neat design.
We count the number of sections
With a simplified heat engineering calculation, the heat consumption is 100 W per square meter of room area. To find out the required number of radiator sections, multiply the footage of the room by 100 and divide the result by the amount of heat transfer from one section, depending on the temperature of the coolant (it is indicated in the characteristics of the radiator). So, if the area of the room is 16 m², and the heat transfer of the section is 160 W, then the number of sections is 16 × 100/160 = 10 pieces. This calculation method is not accurate, as it does not take into account a number of parameters: for example, the height of the ceilings or the way the radiator is connected. Therefore, it is necessary that the final calculation is performed by a specialist.
Landmarks in the world of radiators
How to determine which models are suitable for your house or apartment? First of all, they must meet a number of requirements that depend on the design of the heating system: the type and pressure of the coolant, the connection diagrams for radiators
to the pipeline.
Radiators give off heat largely due to radiation, so it is not recommended to cover their front surface with decorative elements
The operating pressure in the system can range from 1–3 atm in private cottages and up to 8–10 atm in apartment buildings. In the latter case, you need to be especially careful when choosing radiators, it is better to purchase models with a margin of safety. For example, steel design radiators of the Kimrsky plant of thermal equipment are designed for a working pressure of 15 atm and a test pressure of 22.5 atm, high-pressure Arbonia tubular collectors are designed for a working pressure of 16 atm, and Monolit (Rifar) series models are designed for a working pressure of 100 atm .
The coolant can be not only water, but also a mixture of various liquids with a low freezing point (ethylene glycol, propylene glycol, etc.). Some of them can react chemically with aluminum and cause it to corrode. For low-freezing coolants, it is better to choose radiators in which liquid contact with aluminum is excluded. In this case, models with both a steel case and a bimetallic one are suitable, if the manufacturer indicates that the products can be used with any chemically aggressive coolants (for such bimetallic radiators, the collector is completely made of steel, so they are not inferior to all-steel models in terms of durability).
The radiator connection scheme determines how pipelines supplying and discharging coolant are connected to the device. Three schemes are usually used: lateral, diagonal (hot coolant is supplied through the upper pipe in both cases) and lower (both pipes are connected at the bottom of the radiator). The lower connection option is less efficient from the point of view of heat engineering (by about 15–20%). However, the bottom connection is more aesthetically pleasing. Both universal models of radiators and those designed for only one connection scheme (side or bottom) are produced.
An important advantage of convectors is that they can be placed in a floor or wall niche without significant damage to the quality of work.
Are the design and material of the radiator important? Until recently, it was believed that steel or cast-iron tubular appliances are optimal for urban apartment buildings, and, say, panel or sectional aluminum ones are not suitable. But with the advent of radiators made using modern technologies (for example, contact-butt welding is used instead of the classic intersectional assembly using a nipple and a gasket), this opinion is outdated. If the model is designed for high working pressure, then it can be used in urban environments, regardless of the type of construction. The same can be said about the material.
Heat is provided by a convector
Convectors are used for floor installation. In these devices related to radiators, the main heat transfer occurs due to the transfer of heat by hot air flows (convection), while in the first, thermal radiation is added to convection. By design, convectors are tubes with fins. A coolant flows through the pipes and heats the fins. A heated air stream passes through them. The devices are usually equipped with a protective cover. The main advantage of convectors is more efficient heat transfer (therefore, the devices are compact), and the disadvantage is that unwanted air flows (drafts) can form during operation.
Go to the floor?
In most rooms, heating radiators are traditionally installed in the window sill. With this placement, good heat transfer is ensured, especially with an open window, when cold street air is cut off by an ascending warm stream. However, today, double-glazed windows with good thermal insulation are mainly used, without the influx of cold air from the window, so the need to install radiators under the windows is no longer so obvious. Heating appliances are increasingly placed on the walls, in the floor and even inside the walls of the premises. Moreover, if the latter option (for example, system INSIDE (REGULUS) products is still considered exotic, then floor convectors have become quite widespread.
Like conventional convectors, floor models are tubes with lamellar fins, placed in a long and narrow metal casing from 9 to 20 cm high (depending on the model). From above the casing is closed by a lattice. The device is mounted during the laying of the subfloor in such a way that subsequently the grate is flush with the floor covering.
There are models of floor convectors with both natural convection and forced convection, which uses a built-in fan. Systems of the first type are less widespread, since the design of floor convectors is not very convenient for natural air exchange and they are less efficient in terms of heat transfer.
The main advantage of underfloor appliances is that radiators take up absolutely no usable space in the room. As they say, more space and less dust. The device can be mounted in any part of the room where there will be no carpeting, furniture and other interior items.
There are several signs by which you can determine the quality of heating radiators. These include the weight that affects the heat transfer of devices, metal alloy, paint material, the thickness of the manufactured section. Of course, a non-specialist is unlikely to be able to assess the quality of the alloy. All reliable information about the characteristics of radiators and certificates of compliance with international standards are indicated in the technical data sheet of the product. But, unfortunately, today there is no mandatory state certification of radiators. Some manufacturers receive certificates from dubious organizations that do not guarantee the accuracy of the declared data. Buying their products is risky. More reliable are domestic radiators certified according to GOST, for example, products that are manufactured under the Royal Thermo trademark, or according to ISO 9001, when it comes to products made in Europe.
Object Sales Manager at Royal Thermo